12. Which are the special IPv6 addresses?
Auto-return or loopback virtual address. This address is specified in IPv4 with 127.0.0.1 address. In IPv6 this address is represented as ::1.
Not specified address (::). It will never be allocated to any node since it is used to point absence of address.
IPv6 over IPv4 dynamic/automatic tunnels. They are designated as IPv4 compatible IPv6 addresses, and allow to send IPv6 traffic over IPv4 networks in a transparent way. They are represented as ::, for example ::156.55.23.5.
IPv4 over IPv6 addresses automatic representation: they allow that IPv4 only nodes could still work in IPv6 networks. They are designated as "mapped from IPv4 IPv6 addresses. They are represented as ::FFFF:, for example ::FFFF.156.55.43.3
